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Thread: Landing gear thoughts - retract or fixed?

  1. #1
    Mike Switzer's Avatar
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    Landing gear thoughts - retract or fixed?

    One of the major engineering (and cost) challenges for the design I have been working on is retractable landing gear. Life would be a whole lot simpler if I just went with fixed gear.

    What are peoples thoughts on retract vs fixed gear for a 2 seat 200mph design with performance similar to (but slightly heavier than) a Long EZ, RV, Thorp, Mustang II, etc?

    How much benefit would you actually see from retractable gear? I know with production 4 seaters it appears to be approx 20 knots difference, (but they aren't as fast as what I am looking at here)

  2. #2
    Chad Jensen's Avatar
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    IMHO...the weight and complexity of a retractable system to be installed on an airframe that has fantastic performance like those you listed with fixed gear, is not worth the time, effort, money. I used to be a guy that wanted all airplanes to have retractable gear, and I have lots of time in RG airplanes. Other than the "cool factor" of putting the little gear handle in the up position, it's not that big a deal. With an FG airplane, you'll never land it gear up (I hope!), and you won't have gear boxes, hydraulic pumps, actuators, bungees (if needed), etc to worry about.

    All that being said...I do think that RG airplanes are fantastic looking in the air (who doesn't think this!?), but you never see it that way in the cockpit.

    Also, I am fully supportive of anyone making their airplane RG is the spirit of homebuilding, so either way, you win!

    My vote would be to stick with the simple FG design though...
    Chad Jensen
    EAA #755575

  3. #3
    Mike Switzer's Avatar
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    Quote Originally Posted by Chad Jensen View Post
    My vote would be to stick with the simple FG design though...
    I'm beginning to think that would be a whole lot easier...

  4. #4

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    You get more performance gains by reducing weight than anything else. Retract mechanisms are heavy. Careful attention to drag reduction elsewhere can give you as much benefit as retractable gear, without the added weight, cost, and complexity. But there is the undeniable "cool" factor...

  5. #5
    Neil's Avatar
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    I for one do not care for the added weight and complexity of the retract gear aircraft. Insurance companies are more than happy to charge more for hull insurance as well.
    As for the performance aspect of the retract, look at this years Oshkosh race winner. Bruce Hammers Glasair I with a fixed gear and fixed pitch propeller on a 360 Lycoming was the fastest airplane in the field. I think the speed was over 250mph. There are some Glasair IIIs with 540s and retracts that aren't as fast. I know Bruce and his airplane is not a "Race Only" hanger queen. In fact it is his only airplane. Flys it every where he goes. He even piled a tubing bender and some tubing into it and came up to help build an exhaust system on a friends airplane.

    Save the cost and additional weight and pay attention to the wheel pants and intersection fairings.

  6. #6
    Eric Witherspoon's Avatar
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    I'm with the other guys. Just look at the examples you list. Other than the retract nose gear on the Long, they're all fixed. And I believe those canards don't get hit with much of an insurance penalty because nose-gear-up is designed to be not much of an event (scrape the hockey puck, no prop strike). When it's my money buying every last pump, limit switch, linkage, bearing, etc. I'd much rather be buying a machined steel tube and be done with it. Reminds me of a quote attributed to Bill Lear - "You don't have to fix what you leave out."
    Murphy's 13th: Every solution breeds new problems...

    http://www.spoonworld.com

  7. #7
    Mike Switzer's Avatar
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    OK, I'm convinced. Fitting tubular main gear from a 172 would make things a whole lot simpler. (I thought about gear from a 150/152 but that might be a bit light for what I have in mind)

    Just gotta decide if I want a steerable or castering nosewheel. I figure castering is probably lighter (and simpler)

  8. #8
    steveinindy's Avatar
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    As for the performance aspect of the retract, look at this years Oshkosh race winner.
    Is that limited to piston aircraft?

  9. #9
    steveinindy's Avatar
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    I'd much rather be buying a machined steel tube and be done with it.
    The only issue with that is that if you land hard, your spine will be absorbing most of the shock. Worse case scenario, that steel tube is driven back into the cockpit. I've seen this in one crash I went to the scene of; luckily the rod missed the pilots knee (and the large artery located right behind it) by about an inch. One really has to weigh whether you think simplicity is better than an improvement in crash safety or at least figure out how to strike a balance between the two.

    Whatever you do, make sure the landing gear are positioned in such a way that if they are driven upward in a crash that they will not strike the fuel tanks or penetrate the cabin. This goes for both fixies and retracts.

  10. #10

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    I'll put my vote on fixed gear as well.

    Never add a single moving part that isn't absolutely required!
    The opinions and statements of this poster are largely based on facts and portray a possible version of the actual events.

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